Nickel alloy pipes (Inconel, Hatelloy, Alloy 20, Monel, Nickel 200) are renowned for their exceptional resistance to corrosion, high-temperature performance, and strength, making them ideal for challenging environments encountered in the petrochemical, aerospace, marine, and nuclear industries. The American Society for Testing and Materials (ASTM) specifies various grades of nickel alloy pipes, each tailored for specific applications and environments. This article explores the diverse range of ASTM nickel alloy pipe grades, highlighting their unique characteristics and applications.
NICKEL ALLOY PIPES
DEFINITION
Nickel alloy pipes are high-performance piping materials made from alloys primarily consisting of nickel along with various combinations of other elements such as chromium, molybdenum, copper, and iron. These additional elements are carefully selected and blended to achieve specific properties that enhance the performance of the pipes in various applications.
The defining characteristic of nickel alloy pipes is their exceptional resistance to corrosion, high temperatures, and oxidative environments, making them ideal for use in harsh conditions where conventional stainless steel or carbon steel materials might fail.
KEY PROPERTIES OF NICKEL-ALLOY PIPES
- Corrosion Resistance: Nickel alloys are renowned for their ability to withstand corrosion in a wide range of chemical environments, including acidic, alkaline, and chloride-containing environments. This makes them suitable for use in chemical processing, petrochemical industries, and marine applications.
- High-Temperature Performance: Many nickel alloys maintain their strength, ductility, and resistance to oxidation at temperatures that would compromise or degrade most other materials. This characteristic is crucial for applications in aerospace, power generation, and heat treatment industries.
- Durability: Nickel alloy pipes offer excellent durability and longevity, even in demanding operational conditions. Their robustness reduces the need for frequent replacements and maintenance, contributing to cost savings over the life of a project.
- Versatility: The wide range of nickel alloy compositions available allows for the selection of materials tailored to specific environmental conditions and operational requirements. From high-strength, high-temperature applications to those requiring superior corrosion resistance, there is a nickel alloy suited to almost any challenging industrial scenario.
MAJOR APPLICATIONS
Given their outstanding properties, nickel alloy pipes are used in a variety of demanding applications, including:
- Chemical Processing: Handling of aggressive chemicals, acids, and solvents at various temperatures and pressures.
- Oil and Gas Industry: Applications include downhole piping, processing equipment, and offshore oil drilling and production where resistance to sour gas environments is required.
- Power Generation: Used in superheaters, re-heaters, and other high-temperature components of power plants, including nuclear reactors.
- Aerospace: Components exposed to high temperatures and corrosive fuels or oxidizing environments.
- Desalination and Water Treatment: Piping systems that resist chloride-induced corrosion, making them suitable for seawater desalination plants.
MAIN TYPES OF NICKEL ALLOYS
Alloy Type/Name | Characteristics | Applications |
---|---|---|
Nickel-Copper (Monel®) | Excellent corrosion resistance in seawater; resistant to a range of acids and alkalis; strong and ductile. | Marine engineering, chemical processing equipment, oil & gas valves, and pumps. |
Nickel-Chromium (Inconel®) | High-temperature strength; excellent resistance to oxidation and corrosion. | Aerospace, nuclear reactors, exhaust systems, high-temperature applications. |
Nickel-Chromium-Iron (Incoloy®) | Good strength; excellent resistance to oxidation and carburization at high temperatures. | Furnace components, chemical processing, petroleum refining. |
Nickel-Molybdenum (Hastelloy® B) | Exceptional resistance to reducing acids; highly resistant to stress-corrosion cracking. | Chemical processing industries, especially with corrosive acids. |
Nickel-Chromium-Molybdenum (Hastelloy® C) | Superior resistance to oxidizing media; excellent performance in mixed acid/chloride environments. | Pollution control, chemical processing, waste treatment. |
Nickel-Iron-Chromium (Alloy 800/Incoloy® 800 series) | Resistant to oxidation and carburization; moderate sulfur resistance at high temperatures. | High-temperature industrial applications, power generation. |
Precipitation Hardened Nickel Alloys | Heat treatable for higher strength without compromising toughness. | Aerospace components, oil & gas industry for high-strength, corrosion-resistant parts. |
Nickel-titanium (Nitinol) | Unique shape memory and superelastic properties; excellent corrosion resistance; biocompatibility. | Medical devices, actuators, and orthodontic equipment. |
Nickel-Silicon (Ni-Si Alloys) | High strength and electrical resistivity; good corrosion resistance. | Electrical heating elements, resistance wire, control resistors. |
Nickel-Iron (Alloy 42, Kovar®) | Controlled thermal expansion properties; matches glass and ceramic expansion for sealing. | Glass-to-metal seals, electronic tube components, aerospace and semiconductor applications. |
Nickel-Chromium-Cobalt (Waspaloy, Haynes®) | Excellent strength at high temperatures; resistance to oxidation and corrosion. | Gas turbine engines, aerospace components, and high-temperature fasteners. |
ASTM SPECIFICATIONS FOR NICKEL ALLOY PIPES
Nickel Alloy Grade | ASTM Specification | Description |
---|---|---|
Nickel 200 | ASTM B160, B161, B162 | Pure nickel with excellent corrosion resistance and good mechanical properties. |
Monel® 400 | ASTM B164, B165, B127 | Nickel-copper alloy with excellent corrosion resistance in a wide range of media. |
Inconel® 600 | ASTM B166, B167, B168 | A nickel-chromium alloy with good oxidation resistance at high temperatures. |
Inconel® 625 | ASTM B443, B444, B446 | Nickel-chromium-molybdenum alloy with outstanding strength and toughness from cryogenic to high temperatures. |
Hastelloy® C-276 | ASTM B574, B575, B622 | Nickel-molybdenum-chromium alloy with excellent corrosion resistance in severe environments. |
Alloy 20 | ASTM B473, B464, B468 | Nickel-chromium-molybdenum alloy designed to resist corrosion in sulfuric acid environments. |
Incoloy® 800 | ASTM B408, B409, B564 | Nickel-iron-chromium alloy with good strength and resistance to oxidation and carburization. |
Alloy 400 (Monel®) | ASTM B564, B127, B164 | Nickel-copper alloy with high strength and excellent corrosion resistance in a range of acidic and alkaline environments. |
Nitinol | ASTM F2063 | Nickel-titanium alloy is known for its unique shape memory and superelastic properties. |
Waspaloy | ASTM B637 | The nickel-chromium-cobalt alloy used for its strength and stability at high temperatures. |
Hastelloy® B-2 | ASTM B333, B335 | Nickel-molybdenum alloy with exceptional resistance to reducing environments. |
Hastelloy® X | ASTM B435, B572 | High-temperature, nickel-chromium-iron-molybdenum alloy with good oxidation resistance. |
LEADING MANUFACTURERS
The market for nickel-alloy pipes is way more concentrated than other, more common, grades for pipes. Below is a list of some well-known manufacturers and suppliers in the industry:
Special Metals Corporation
A leading global producer, Special Metals is known for its extensive range of nickel alloys, including Inconel, Incoloy, Monel, and Nimonic alloys. They offer a wide variety of forms, including pipes.
Haynes International
Specializing in corrosion-resistant and high-temperature alloys, Haynes International produces high-quality Hastelloy and other nickel-based alloys suitable for challenging environments.
Sandvik Materials Technology
A global industrial group offering advanced stainless steels and special alloys such as Sanicro for corrosion-resistant applications. Sandvik provides a wide range of nickel alloy pipes and tubes.
VDM Metals
With a broad portfolio of nickel alloys and high-performance materials, VDM Metals is known for its innovative alloy solutions tailored to demanding applications.
ATI (Allegheny Technologies Incorporated)
ATI produces a diverse range of specialty metals, including nickel-based alloys designed for high temperatures and corrosive environments. Their products are used in aerospace, oil and gas, and chemical processing industries.
Outokumpu
Although primarily known for its stainless steel products, Outokumpu also offers high-performance nickel alloys for various applications, emphasizing quality and sustainability.
Aperam
Aperam is a global player in the stainless steel and specialty alloys sector, including nickel alloys, focusing on sustainability and innovation.
Jindal Stainless
One of the largest stainless steel conglomerates in India, Jindal Stainless also ventures into nickel alloy products for diverse industrial applications.
FEATURES BY NICKEL-ALLOY GRADE
CHEMICAL COMPOSITION OF MAJOR NICKEL-ALLOY GRADES
Alloy Name | Nickel (Ni) | Chromium (Cr) | Molybdenum (Mo) | Iron (Fe) | Copper (Cu) | Aluminum (Al) | Titanium (Ti) | Carbon (C) | Other Elements |
---|---|---|---|---|---|---|---|---|---|
Inconel 600 | 72 | 14-17 | – | 6-10 | – | – | – | 0.15 | – |
Inconel 625 | 58-63 | 20-23 | 8-10 | 5 max | – | 0.4 | 0.4 | 0.10 | Nb 3.15-4.15 |
Inconel 718 | 50-55 | 17-21 | 2.8-3.3 | Balance | – | 0.2-0.8 | 0.65-1.15 | 0.08 | Nb+Ta 4.75-5.5 |
Hastelloy C-276 | 57 | 14.5-16.5 | 15-17 | 4-7 | – | – | – | 0.01 | W 3-4.5, V 0.35 max |
Monel 400 | 63 min | – | – | 2.5 max | 28-34 | – | – | 0.3 | – |
Alloy 20 | 32-38 | 19-21 | 2-3 | 31-44 | 3-4 | – | – | 0.07 | Nb 0.1-0.3 |
Hastelloy B-2 | Balance | 1 max | 26-30 | 2 max | – | – | – | 0.02 | – |
Incoloy 800 | 30-35 | 19-23 | – | 39.5 min | – | 0.15-0.60 | 0.15-0.60 | 0.1 | – |
Incoloy 825 | 38-46 | 19.5-23.5 | 2.5-3.5 | 22 min | 1.5-3 | 0.2 max | 0.6-1.2 | 0.05 | Ti 0.6-1.2 |
Nitinol | 55 | – | – | – | – | – | 45 | – | – |
Please note:
- The percentages are approximate and can vary based on the specific alloy formulation and manufacturer.
- “Balance” indicates that the remaining composition is primarily nickel, after accounting for the specified elements.
- Some alloys may contain additional elements in trace amounts not listed in this table, which can affect their properties and applications.
- “Nb” stands for Niobium, “Ta” for Tantalum, “W” for Tungsten, and “V” for Vanadium, which are elements that can significantly influence the alloy’s characteristics.
This table provides a snapshot of the diverse compositions of major nickel alloys and underscores the complexity and tailored properties of these advanced materials for specific industrial applications.
NICKEL 200/201
Nickel 200 pipes are made from commercially pure nickel that possesses high thermal and electrical conductivities, and magnetic properties, and is highly resistant to various corrosive environments.
With a nickel content of approximately 99.6%, Nickel 200 (UNS N02200) is characterized by its exceptional resistance to caustic alkalis and other corrosive media at different temperatures.
This grade of nickel is designated as UNS N02200, and it is similar to Nickel 201 (UNS N02201), which is a low-carbon version of Nickel 200 and is preferred for applications where low gas content and low vapor pressure are required.
Key Properties of Nickel 200 Pipes
- Corrosion Resistance: Nickel 200 pipes offer excellent resistance to corrosion by distilled and natural waters, as well as by many organic substances. They are also resistant to caustic alkalis and to a range of acidic environments, except for those containing oxidizing acids.
- High Thermal Conductivity: These pipes can efficiently transfer heat, making them suitable for heat exchangers and other applications requiring good thermal conductivity.
- Electrical Conductivity: Nickel 200’s high electrical conductivity makes it ideal for electronic applications.
- Magnetism: Nickel 200 is magnetic at room temperature, which can be advantageous in certain applications.
- Fabrication and Weldability: Nickel 200 can be easily fabricated and welded, offering flexibility in manufacturing processes.
Applications of Nickel 200 Pipes
Due to their corrosion resistance and high thermal and electrical conductivities, Nickel 200 pipes find applications in various industries:
- Chemical Processing: Used in the manufacture and handling of sodium hydroxide, particularly at temperatures above 300°C where steel would succumb to stress-corrosion cracking.
- Food Processing: Their corrosion resistance makes them suitable for food processing equipment and handling of foods, synthetic fibers, and alkalis.
- Electrical and Electronic Industries: Utilized in the production of electrical components, including leads, battery components, and heat exchangers.
- Aerospace: Due to their thermal conductivity, these pipes are used in aerospace applications where high-temperature resistance is required.
- Marine: Their resistance to seawater corrosion makes them applicable in marine engineering and desalination plants.
Considerations and Limitations
While Nickel 200 pipes offer excellent corrosion resistance and mechanical properties, they are not recommended for use in environments where they might be exposed to sulfur compounds that can induce stress-corrosion cracking. Additionally, they should be carefully selected for use in oxidizing acid environments, where higher alloyed materials might be more suitable.
Nickel 200 pipes represent an optimal choice for industries requiring materials that offer corrosion resistance, high thermal and electrical conductivities, and effective performance in a wide temperature range. Their versatility and durability make them an invaluable resource in the chemical processing, food processing, electrical, aerospace, and marine industries, among others. Despite their specific limitations, the careful selection of Nickel 200 pipes based on the application environment can provide efficient and reliable solutions to a broad spectrum of industrial challenges.
MONEL® 400/500 PIPES
Monel pipes, made from a family of nickel-copper alloys, are renowned for their exceptional strength, corrosion resistance, and durability in various aggressive environments. Monel’s unique composition, primarily of nickel and copper, with small amounts of iron, manganese, carbon, and silicon, contributes to its notable properties. The most commonly used grade in this family is Monel 400, although other grades, like Monel K-500, also find specific applications due to their enhanced properties.
Key Properties of Monel Pipes
- Corrosion Resistance: Monel pipes exhibit excellent resistance to a wide range of corrosive environments, including seawater, hydrofluoric acid, sulfuric acid, and alkalis. They are particularly valued for their performance in marine and chemical processing environments.
- Strength: Despite their high nickel content, Monel pipes possess a higher strength level than many other nickel alloys, especially at elevated temperatures. This makes them suitable for high-pressure applications.
- Toughness: Monel maintains good toughness over a considerable temperature range, making it useful in cold environments where other materials might become brittle.
- Thermal Conductivity: Monel has good thermal conductivity, beneficial in applications requiring heat exchange or dissipation.
Common Applications of Monel Pipes
- Marine Engineering: Due to their excellent resistance to seawater corrosion, Monel pipes are used in marine applications, including shipbuilding, seawater intakes, and marine fixtures.
- Chemical Processing: Monel’s resistance to acids and alkalis makes it suitable for transporting corrosive chemicals, manufacturing chemical equipment, and handling organic compounds.
- Oil and Gas: Monel pipes are used in oil refinery piping, sour gas service, and offshore oil rig applications, where their corrosion resistance is a valuable asset.
- Power Generation: Utilized in feedwater heaters, steam generators, and other components exposed to corrosive substances and high temperatures.
Grades of Monel and Their Specific Uses
- Monel 400: The most widely used Monel alloy, offering excellent general corrosion resistance, good weldability, and moderate to high strength. It is the standard material for marine and chemical processing applications.
- Monel K-500: Enhanced strength and hardness due to the addition of aluminum and titanium, making it suitable for chains, cables, springs, valve trim, fasteners for marine service, and oil well drilling collars.
Installation and Fabrication
Monel pipes can be welded, machined, and formed using standard methods, although working with Monel requires experience due to its work-hardening properties. Welding Monel pipes typically involves using Monel filler metal to ensure the joint has the same corrosion resistance and strength as the base metal.
Monel pipes represent a versatile solution for challenging environments, offering a unique combination of corrosion resistance, strength, and durability. Their ability to perform under corrosive conditions, coupled with their mechanical properties, makes them an invaluable material in industries ranging from marine engineering to chemical processing. Despite their higher cost compared to standard stainless steel, their longevity and reliability in harsh environments often justify the initial investment, making them a preferred choice for critical applications.
CUPRONICKEL PIPES (90/10 & 70/30 TYPES)
Cupronickel pipes are made from an alloy of copper, nickel, and strengthening elements such as iron and manganese. This combination results in a material that exhibits superior corrosion resistance, particularly in marine environments, alongside excellent thermal stability and durability. Cupronickel alloys are most commonly found in two variations: 90/10 (90% copper, 10% nickel) and 70/30 (70% copper, 30% nickel), with the numbers denoting the proportions of copper and nickel in the alloy.
Key Properties of Cupronickel Pipes
- Corrosion Resistance: Cupronickel pipes offer excellent resistance to seawater corrosion, including resistance to biofouling, making them ideal for marine applications.
- Thermal Stability: These pipes maintain their mechanical properties over a wide temperature range, making them suitable for applications involving thermal cycling or where temperature stability is required.
- Good Fabricability: Cupronickel alloys can be easily welded, fabricated, and formed, allowing for their use in various complex shapes and configurations.
- Antimicrobial Properties: The copper content in cupronickel provides antimicrobial properties, which can be beneficial in reducing biofouling in marine environments and maintaining cleanliness in potable water systems.
Applications of Cupronickel Pipes
Given their unique combination of properties, cupronickel pipes find extensive use in several critical areas:
- Marine Engineering: Used extensively in shipbuilding for piping systems, heat exchangers, and condensers due to their corrosion resistance to seawater.
- Desalination Plants: Applied in the multi-stage flash distillation process as heat exchanger tubing, where resistance to corrosion and biofouling is crucial.
- Offshore Oil and Gas: Utilized in offshore oil and gas platforms for fire water systems, hydraulic lines, and cooling water circuits.
- Power Generation: Employed in cooling systems and condensers in power plants, especially in coastal locations where seawater is used as a coolant.
- Coinage and Musical Instruments: Beyond industrial applications, cupronickel alloys are also used in the production of coins and in the manufacture of certain musical instruments, taking advantage of their corrosion resistance and aesthetic appeal.
Fabrication and Machining
Cupronickel pipes can be fabricated using standard metalworking techniques, including welding, soldering, and bending. The material’s work-hardening characteristics require attention during machining to prevent excessive tool wear. Precautions should be taken to avoid galvanic corrosion when cupronickel is in contact with different metals, typically by using appropriate insulating materials or coatings.
Considerations for Use
The choice between the 90/10 and 70/30 alloys often depends on the specific environmental conditions and mechanical requirements of the application, with the 70/30 alloy generally offering higher corrosion resistance and strength at the cost of slightly lower thermal conductivity and higher material expense.
Cupronickel pipes are a preferred material in marine and other corrosive environments, valued for their corrosion resistance, durability, and thermal stability. Their wide range of applications, from shipbuilding to desalination and beyond, showcases the versatility and reliability of cupronickel alloys in facing some of the most challenging conditions encountered in industry and engineering.
INCONEL® 600 PIPES
INCONEL® 600, designated as UNS N06600, is a nickel-chromium alloy that is known for its excellent resistance to oxidation at high temperatures and to corrosion in a wide range of corrosive environments, including those containing sulfur compounds and chloride ions.
This makes INCONEL® 600 pipes highly suitable for demanding applications where both heat and corrosion resistance are required.
Key Properties of INCONEL® 600 Pipes
- Corrosion Resistance: INCONEL® 600 offers outstanding resistance to chloride-ion stress-corrosion cracking, corrosion by high-purity water, and caustic corrosion. The alloy’s resistance to corrosion by many organic and inorganic compounds, along with its excellent resistance to chloride-ion stress-corrosion cracking, makes it a versatile material.
- High-Temperature Resistance: The high chromium content provides excellent resistance to oxidation, allowing INCONEL® 600 to maintain strength and resistance to scaling at high temperatures up to 2000°F (1093°C).
- Strength: The solid solution strengthening of chromium and nickel in INCONEL® 600 provides high strength and good workability under a wide range of temperatures.
- Fabricability: Despite its strength, INCONEL® 600 can be easily formed and welded, making it suitable for a variety of fabrication processes.
Applications of INCONEL® 600 Pipes
INCONEL® 600’s unique combination of properties makes it suitable for a range of challenging environments:
- Chemical Processing: Pipes and tubes made of INCONEL® 600 are used in reactors and vessels where resistance to heat and corrosion is essential.
- Heat Treatment: Employed in retorts, muffles, and other components in furnaces due to its resistance to oxidation and scaling at high temperatures.
- Aerospace: Used in exhaust liners, turbine seals, and other aerospace components where high-temperature resistance is crucial.
- Nuclear: INCONEL® 600 is utilized in the nuclear field for reactor cores and control rod components due to its resistance to corrosion by high-purity water.
- Power Generation: Applied in superheater tube supports and steam generator tubing, where its resistance to heat and corrosion provides reliability under the demanding conditions of power plants.
Considerations for Use
While INCONEL® 600 offers excellent high-temperature strength and corrosion resistance, it is essential to consider the specific environment in which it will be used to ensure its suitability. For example, the alloy may experience embrittlement when exposed to sulfur compounds at high temperatures. Therefore, understanding the operational conditions is critical for selecting the appropriate alloy for your application.
INCONEL® 600 pipes are an excellent choice for applications requiring a combination of high-temperature strength, corrosion resistance, and durability. Their versatility makes them ideal for use in a wide range of industrial sectors, including chemical processing, aerospace, nuclear, and power generation. With proper selection and maintenance, INCONEL® 600 pipes can provide reliable performance in some of the most challenging environments.
INCONEL® 625 PIPES
INCONEL® 625, designated as UNS N06625, is a nickel-chromium-molybdenum alloy with an addition of niobium that acts with the molybdenum to stiffen the alloy’s matrix, providing high strength without a strengthening heat treatment. This alloy is known for its exceptional resistance to a wide range of severely corrosive environments, high-temperature effects such as oxidation and carburization, and its high strength and toughness from cryogenic temperatures to 1800°F (982°C). INCONEL® 625 pipes leverage these properties, making them ideal for demanding applications across various industries.
Key Properties of INCONEL® 625 Pipes
- Corrosion Resistance: INCONEL® 625 offers outstanding resistance to chloride-ion stress-corrosion cracking, reducing environments, and oxidizing conditions. This includes resistance to seawater, pitting, and crevice corrosion, making it suitable for marine applications.
- High-Temperature Performance: The alloy maintains its strength over a wide temperature range. Its resistance to oxidation and carburization at high temperatures is particularly noteworthy.
- Strength and Toughness: The unique composition of INCONEL® 625 provides high tensile, creep, and rupture strength across a wide temperature range, including cryogenic temperatures.
- Fabricability: Despite its strength, INCONEL® 625 can be welded and formed relatively easily, which is beneficial for complex designs and installations.
Applications of INCONEL® 625 Pipes
The combination of corrosion resistance, high-temperature capability, and strength makes INCONEL® 625 pipes suitable for a broad range of applications:
- Oil and Gas: Used in offshore oil and gas rigs for brine heaters, seawater piping, and underwater equipment due to its excellent corrosion resistance in seawater.
- Aerospace: Applied in exhaust systems, engine thrust-reverser systems, and special seawater applications due to its high strength and resistance to oxidation.
- Chemical Processing: INCONEL® 625 pipes are utilized in reactor cores and control systems where resistance to corrosive substances is required.
- Nuclear Industry: Suitable for reactor core and control rod components in nuclear water reactors due to its resistance to a wide range of corrosive elements and high-temperature conditions.
- Power Generation: Used in superheater tubing and in heat exchangers that require excellent corrosion resistance and strength at high temperatures.
Considerations for Use
While INCONEL® 625 offers exceptional performance in many harsh environments, it’s important to carefully consider the specific conditions of each application, including potential exposure to corrosive substances and the range of operational temperatures. Selection should be based on a thorough understanding of the environmental conditions to ensure the alloy’s properties are fully leveraged for long-term reliability and performance.
INCONEL® 625 pipes represent a superior choice for challenging environments where a combination of corrosion resistance, high-temperature capability, and strength are crucial. Their wide use in industries such as oil and gas, aerospace, chemical processing, nuclear, and power generation highlights their versatility and effectiveness in facing some of the most demanding conditions encountered in industrial applications. With proper selection and maintenance, INCONEL® 625 pipes can offer durable and reliable performance, contributing significantly to the success and efficiency of various projects.